1. Technical Field
The present invention relates to a gas cell, a quantum interference device, an atomic oscillator, an electronic device, and a moving object.
2. Related Art
As an oscillator having excellent long-term frequency stability, an atomic oscillator which oscillates on the basis of energy transition of atoms of an alkali metal such as rubidium or cesium is known.
In general, an operation principle of the atomic oscillator is mainly classified into a method that uses a double resonance phenomenon of light and microwaves and a method that uses a quantum interference effect (coherent population trapping (CPT)) of two types of light having different frequencies.
Even in any method of the atomic oscillator, typically, the alkali metal is sealed in a gas cell along with a buffer gas (for example, see JP-A-2010-245805).
Recently, due to the demand for a reduction in size of the atomic oscillator, a reduction in size of the gas cell is required. In a small gas cell, the pressure of the buffer gas needs to be increased for the purpose of enhancing short-term frequency stability.
However, in a case where the pressure of the buffer gas is increased (for example, 30 Torr or higher), when neon is used as the buffer gas, there is a problem in that long-term frequency stability is degraded. It is inferred that this problem occurs because neon has a tendency to easily diffuse toward the inner wall of the gas cell and the tendency becomes significant when the pressure in the gas cell is increased.